Coal Tar and Coal-Tar Pitches Occupational Exposures

Coal Tar and Coal-Tar Pitches Occupational Exposures

Overview

Inhalation and dermal contact are the most important routes of occupational exposure.[1] CAREX Canada estimates that approximately 7,600 Canadian workers are exposed to coal tar and coal-tar pitches in their workplace.

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Among Canadian industries, the largest exposed groups are aluminum production and processing; foundation, structure, and building contractors; and highway, street, and bridge construction. The largest exposed occupational groups are roofers and shinglers, followed by construction trades helpers and labourers, and machine operators in mineral and metal processing.

Other industries with potential for occupational exposure to coal tar and coal-tar pitch include those associated with coke production, coal gasification, steel foundries, and installation of electrical equipment.[1,2] Exposure may also occur when producing or using refractory bricks, paints, enamels, or coatings.[2]

Prevalence Estimate

Results show that approximately 7,600 Canadians are exposed to coal tar and coal tar pitches in their workplaces; 93% of these workers are male. The largest exposed industrial groups are alumina and aluminum production and processing, foundation, structure, and building exterior contractors, highway, street and bridge construction, and foundries.

When exposure is examined by occupation, the largest exposed groups are roofers and shinglers (2,200 exposed), construction trades helpers and labourers (800 exposed), machine operators in mineral and metal processing (700 exposed), and heavy equipment operators (600 exposed).

Workers exposed to coal tar and coal tar pitches by industry

Workers exposed to coal tar and coal tar pitches by region

Click the second tab to view total number of workers exposed.

* = < 50 workers
Methods and Data

Our Occupational Approach page outlines the general approach used to calculate prevalence and exposure level estimates for workplace exposures.

Data Sources

Data used in developing the occupational estimates for coal tar and coal tar pitches were collected from several sources:

  1. The Canadian Workplace Exposure Database (CWED) contains over 500 measurements for coal tar and coal tar pitches exposure. These measurements were collected during the years 1981 to 2004 in Ontario and British Columbia workplaces.
  2. Canadian and US scientific peer reviewed publications that addressed coal tar and coal tar pitches exposure in Canada and the United States.
  3. Grey literature including technical reports from governments and international bodies.

Prevalence Estimate Method

CAREX defines exposure to coal tar and coal tar pitches as dermal exposure at work to levels significantly exceeding non-occupational background levels. Inhalation exposures to coal tar and coal tar pitch volatiles are not included in our exposure estimate as they overlap with exposures to polycyclic aromatic hydrocarbons (PAHs). Likewise, exposure to creosotes and naphthalene are not considered for this report. PAHscreosotes and naphthalene are addressed under their specific CAREX occupational exposure estimates.

To determine the number of workers potentially exposed to coal tar and coal tar pitches at work, CAREX occupational exposure experts used methods previously established in other peer-reviewed CAREX projects in Europe. A series of steps were taken to assign exposure proportions to occupations and industries at risk of exposure to coal tar and coal tar pitches.

  1. Occupations and industries at risk of possible exposure to coal tar and coal tar pitches were identified using any combination of data sources described above.
  2. The total number of workers in each identified occupation and industry intersection was obtained from Statistics Canada 2006 census data.
  3. A percentage of workers exposed was assigned to that occupation and industry intersection. Percentages were determined by consultation with existing evidence in the data sources, previously established methods from the Europe CAREX estimates and the expert judgement of CAREX occupational hygienists.
  4. The number of workers in the identified group is multiplied by the assigned percentage to calculate the prevalence estimate of workers exposed to coal tar and coal tar pitches.
Sources

1. US National Library of Medicine. Hazardous Substances Data Bank (Search term: ‘coal tar and coal-tar pitches’)
2. National Toxicology Program (NTP). 14th Report on Carcinogens for Coal tar and Coal-tar Pitches (2016) (PDF)

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